[gas][aarch64] Add the v8.6 Data Gathering Hint mnemonic [10/X]

[gas][aarch64] Add the v8.6 Data Gathering Hint mnemonic [10/X]

Hi,

This patch is part of a series that adds support for Armv8.6-A
to binutils.

In this last patch, the new Data Gathering Hint mnemonic is introduced.

Committed on behalf of Mihail Ionescu.

gas/ChangeLog:

2019-11-07  Mihail Ionescu  <mihail.ionescu@arm.com>

	* testsuite/gas/aarch64/dgh.s: New test.
	* testsuite/gas/aarch64/dgh.d: New test.

opcodes/ChangeLog:

2019-11-07  Mihail Ionescu  <mihail.ionescu@arm.com>

	* opcodes/aarch64-tbl.h (V8_6_INSN): New macro for v8.6 instructions.
	(aarch64_opcode_table): Add data gathering hint mnemonic.
	* opcodes/aarch64-dis-2.c: Account for new instruction.

Is it ok for trunk?

Regards,
Mihail